Patients will be given a bottle of 5% Dexpanthenol mouthwash and they are asked to rinse 10 ml of it three times a day. At the onset of mucositis and then for 4 subsequent weeks they will be examined to evaluate the condition of their oral mucosa.By the advent of mucositis stage 4 ,at any time during the 4 weeks of study,the patient would be out.if any patient shows allergic reaction to dexpanthenol,he/she would be out of study too.